1. Field of the Invention
The present invention relates to handpieces containing an interior electrical winding, which handpieces are for use in treating mammals. More particularly the present invention relates in a preferred embodiment to ultrasonic dental/medical hand tools and more especially to an ultrasonic dental handpiece which can withstand the rigors of hundreds of cycles of sterilization using anyone of a number of currently widely used sterilization methods and equipment including autoclaving, dry heat at 190.degree. C. and Chemical, while fully assembled without unacceptable detrimental effects to the handpiece. Specifically, the electrical components of the handpiece can be subjected to any of these sterilization techniques without material damage with fluid and heat entering the interior of the handpiece.
2. Description of the Prior Art
Ultrasonic dental handpieces employed during dental procedures for cutting or cleaning are well known.
One such example is U.S. Pat. No. 4,492,574 to Warrin et al., which teaches an ultrasonic endodontic dental handpiece having a coil for establishing an alternating magnetic field, the housing having a cooling fluid inlet at one end and being open at the other end for receiving and supporting a removable insert.
Today, cross contamination has become a major concern in the medical and dental fields. Bacteria and viruses from one patient's mouth can be transferred to another patient if the handpiece is not adequately sterilized. Therefore, sterilization of dental instruments has become almost mandatory. However, due to the sensitive nature of the electrical and mechanical components involved with ultrasonic handpieces, sterilization of the entire handpiece was previously limited.
Prior to this invention the more usual method used to cleanse and disinfect ultrasonic handpieces was to wipe the exterior of the handpiece using a disinfecting solution. Where autoclaving was alleged to be acceptable, its use was limited to handpieces of simpler design having only heavy gauge wire windings.
In many prior art handpieces a coil of conductive wire within the handpiece was connected permanently by a cable to a power source. An oscillating current within the coil in the handpiece produced a magnetic field to induce motion within a magnetostrictive element separable and removably inserted within the magnetic field within the handpiece. The magnetostrictive element was connected by a metal body to a dental tool which was caused to vibrate at ultrasonic speeds to clean and reduce teeth, calculus, cartilage and bone. High temperature and steam sterilization methods were not suitable for sterilizing these handpieces because they would cause short-circuiting in the coils and connections and degradation of mechanical parts, resulting in impractically short useful life.
The present invention has overcome the problems encountered in the art by providing an ultrasonic handpiece which is removed from the cable and effectively sterilized without the need for further disassembly by one of several methods available, including autoclave and other steam sterilization techniques, high temperature dry sterilization, Chemiclave.RTM., and using other liquid sterilants at room and elevated temperatures. The invention is broadly applicable to dental/medical handpieces of diverse uses including handpieces such as for dental scalers, medical scalers, endodontic, orthopedic and nasal medical handpieces and combinations thereof. The preferred embodiment of the invention is in dental handpieces.
While described in detail in its most preferred embodiment of a dental handpiece the present invention is directly applicable to other dental, medical and veterinary tools having electric coils proximate to a patient so that superior sterilization is indicated by good dental, medical or veterinary practice.